Linkage for an ejector type bucket loader



Jan. 14, 1969 E. J. MOYER LINKAGE FOR AN EJECTOR TYPE BUCKET LOADER Filed June 22, 1967 Sheet INVENTOR. EDWARD J. MOYER 4 M! ATTORNEYS Jan. 14, 1969 E. J. MOYER 3,421,236

LINKAGE FOR AN EJECTOR TYPE BUCKET LOADER Filed June 22, 1967 Sheet 2 of 2 I d; "f I g g H I INVENTOR. EDWARD J. MOYER ATTORNEYS United States Patent O 3,421,236 LINKAGE FOR AN EJECTOR TYPE BUCKET LOADER Edward J. Moyer, Morton, Ill., assignor to Caterpillar Tractor Co., Peoria, Ill., a corporation of California Filed June 22, 1967, Ser. No. 648,145 U.S. Cl. 37-117.5 8 Claims Int. Cl. E02f 3/76; E021? 9/00; 1360;: 1/20 ABSTRACT OF THE DISCLOSURE An improvement in tractor loaders having an ejector type bucket, lift arms for raising and lowering the bucket, and tilt linkage for controlling forward and rearward tilting of the bucket. An ejector link extends from the bucket ejector plate to a pivotal connection with the tilt linkage by means of a tilt linkage lever and an ejector lever. The tilt linkage and ejector levers each have contacting surfaces which radially extend from their common pivot connection and pivot into positive contacting relation to subsequetnly pivot the ejector plate forwardly according to operation of the tilt linkage.

Background of the invention The present invention relates generally to bucket loaders and more particularly to a tractor loader having an ejector type bucket wherein the ejector plate is controlled by the tilt linkage associated with the bucket.

Typical tractor loaders of a type having an ejector with the primary purpose of positively unloading material from the bucket, commonly have a pair of lift arms and a tilt linkage for controlling the bucket while the ejector is controlled by a separate hydraulic jack within the bucket assembly. Such a separate hydraulic jack for controlling the ejector undesirably increases the weight of the bucket assembly and further places additional manipulative duties on the loader operator.

It has thus been found desirable to automate the operation of the ejector plate while reducing the weight of components within the bucket assembly. One such solution is to provide a pair of cam surfaces on the rear of the ejector plate with members of the tilt linkage being in sliding contact with those cam surfaces. The cam surfaces are so shaped that the ejector plate is pivoted forwardly in desired relation to the tilt position of the bucket. However, such a cam arrangement for controlling the ejector has generally been found to have an unsatisfactory mechanical advantage causing undue wear in the tilt linkage members acting against the cam surfaces.

Summary of the invention The present invention provides an improved ejector control in tractor loaders having an ejector type bucket, lift arms for raising and lowering the bucket, and a tilt linkage for controlling forward and rearward tilting of the bucket. The bucket includes a pivotal ejector plate which forms the rear Wall of the bucket. A link element is connected to the ejector plate and extends from the ejector plate toward a link actuating portion of the tilt linkage. The ejector plate is moved forwardly in the bucket by the ejector link according to being positive actuating contact in the link actuating portion of the tilt linkage only after an initial portion of the forward tilting of the bucket by the tilt linkage.

Brief description 07 the drawings FIG. 1 is a partial side view in elevation of a tractor loader with its bucket in a loading position;

3,421,236 Patented Jan. 14, 1969 "ice Description of a preferred embodiment Referring now to FIG. 1, a typical tractor loader has a tractor 11 and a bucket assembly 12 which is pivotally connected to the tractor by a pair of lift arms, one of which is indicated at 13, for raising and lowering the bucket. The attitude of the bucket on the lift arm is controlled by a tilt linkage on either side of the tractor, one such tilt linkage being indicated at 14.

The bucket assembly has a floor portion 16 with a cutting blade 17 along its forward edge and an arcuate interior floor surface 18. The bucket floor and a pair of bucket sidewalls, one of which is indicated at 19, are connected to a pair of generally vertical bucket support members located at the rear and to either side of the bucket, one such support member being indicated at 21. A cross beam 22 is connected across the tops of the support members. Each of the lift arms 13 is pivotally connected to one of the bucket support members at a pivot connection 23 and extends rearwardly to a pivot connection 24 with the tractor. A hydraulic jack 26 is pivotally connected between the tractor and each of the lift arms for operating the lift arms to raise and lower the bucket. The tilt linkage on either side of the tractor comprises a first member 27 which is pivotally connected to one of the bucket support members at a pivot connection 28 and extends rearwardly therefrom. A second elongated member 29 is connected to a hydraulic jack 31 by means of a bellcrank member 32 and extends forwardly therefrom. The bellcrank member 32 has a central pivot point 33 which is connected to the hydraulic jack rod and two end pivot points 34 and 36 which are respectively con nected to the tractor adjacent its pivot connection 24 with one of the lift arms and the rearward end of the sec-0nd element 29 to provide for some automatic tilting of the bucket according to the movement of the lift arms to raise and lower the bucket. The rearward end of the first tilt linkage element 27 and the forward end of the second tilt linkage element 29 are pivotally connected at respective points 37 and 38 to a tilt linkage lever 39 which is also pivotally connected to the lift arm 13 generally midway along its length at pivot point 41.

The bucket 12 has an ejector plate 42 which is arcuately shaped, forms the rear wall of the bucket assembly 12 and is pivotally connected to the bucket support members at the top of the bucket assembly by pivot connections 43. Thus, the ejector plate may pivot forwardly from its position at the rear of the bucket with its lower edge 44 sweeping along the arcuate floor surface 18 toward the cutting edge 17.

To provide for automatic control of the eje'ctor plate according to the tilt linkage by apparatus which is of simple and reliable construction, an ejector link 46 is connected to either side of the ejector plate generally adjacent one of the bucket support members at a pivot connection 47. Each ejector link extends rearwardly to a pivot connection 48 with an ejector lever 49. A rearward portion of the ejector lever has a pivot connection 51 with a portion of the tilt linkage lever 39 which is remote from the pivot connection of the tilt linkage lever with the lift arm 13. A generally upward facing contact surface is defined at the upper extremity 52 of the tilt linkage lever 39 as a radial projection from the pivot connection 51 between the tilt linkage lever 39 and the ejector lever 49. The ejection lever 49 has a generally rearward facing contact surface 53 which also radially projects from the pivot point 51. It is readily apparent by comparison of FIG. 1 with subsequent figures, particularly FIGS. 3 and 4, that as the tilt linkage lever 3-9 is forwardly pivoted about its pivot point 41 on the lift arm during forward tilting of the bucket, the angular opening between the contacting surfaces 52 and 53 will be closed and that after this initial forward tilting of the bucket, the tilt linkage lever 39, the ejector lever 49 and the ejector link 46 will form a continuous lever in effect which pivots the ejector plate forwardly according to subsequent forward tilting of the bucket by the tilt linkage. Each ejector lever 49 also has a stop 54 for contacting a rearward extension 56 of the ejector link 46 to limit downward pivoting between the ejector lever 49 and the ejector link 46 as illustrated in FIGS. 1 and 2. Further, each pivot connection 48 between one of the ejector levers 49 and one of the ejector links 46 projects inwardly above the first tilt linkage member 27 and preferably has a bushing 50 thereon (see FIG. 4) to act as a second stop to contact the forward member 27 and limit the forward pivoting of the ejector plate. The geometry of the tilt linkage and the positions of the stops are selected to provide for proper positioning of the bucket and the ejector plate during the hereinbelow descirbed modes of operation.

When the bucket is in a position to commence loading, with the floor of the bucket substantially level with the ground, the interrelation of the ejector link with the tilt linkage permits some freedom of motion in the ejector to prevent binding and the ejector plate is accordingly positioned somewhat forwardly in the bucket as illustrated in FIG. 1. As material enters the bucket during loading, it acts against the ejector plate and tends to move it rearwardly against the bucket supports to permit complete filling of the bucket. This rearward motion of the ejector is accompanied by counterclockwise rotation of the ejec tor lever 49 and the ejector link 46 would pivot downwardly toward the tilt linkage lever 39 such that on subsequent forward tilting of the bucket, the ejector linkage would not perform properly.

It is also apparent from FIG. 1 that if the bucket is raised by the lift arms and forwardly tilted by the tilt linkage to have only its cutting edge 17 in contact with the ground, the ejector plate will be pivoted forwardly to have its sweeping edge 44 aligned with the cutting edge 17 of the bucket. Thus, an effective bulldozing surface may be provided by the combination of the bucket cutting edge 17 and the ejector plate 42.

Referring now to FIG. 3, when the bucket is raised by the lift arms to its normal carry position, the action of the bellcrank member 32 tilts the bucket automatically to permit it to maintain its load. In this carry position, where the bucket is at a preselected and preferred elevation for dumping, for example into a truck, it is to be noted that the angular opening between the contacting surfaces 52 and 53 of the tilt linkage lever and the ejector lever respectively is almost closed such that subse quent forward pivoting of the bucket will be accompanied by forward pivoting of the ejector plate within the bucket. Such a forward pivoting action is illustrated at its completion in FIG. 4 where the contacting surfaces 52 and 53 have made positive contact and the ejector plate has been pivoted forwardly at least to be aligned with the cutting edge of the bucket. Referring further to FIG. 4, when the ejector plate has traversed the bucket floor and completely unloaded materail from the bucket, the bucket floor is substantially level, thereby permitting the tractor loader to depart from its dumping site, for example over the walls of a truck body, without first stopping to again raise the bucket to permit clearance with the truck. Thus, the efficiency of the tractor loader is further increased.

The function of the second stop 50 may also be seen from FIG. 4. As it comes in contact with the forward tilt linkage member 27, it prevents outward swinging of the ejector plate from the bucket to prevent it from impinging or becoming entangled with a structure forward of the bucket during dumping.

I claim:

1. In a tractor mounted loader having a bucket, lift arms pivotally connected to the bucket for raising and lowering the bucket, tilt linkage connected to the bucket for tilting the bucket forwardly and rearwandly and an ejector plate which forms the rear wall of the bucket and is pivotally connected to the bucket to permit forward and rearward pivoting of the ejector plate, the improvement comprising:

a link connected to the ejector plate for controlling the forward and rearward positioning of the ejector plate in the bucket and an ejector lever joined to the link and pivoted to a lever portion of the tilt linkage, the ejector plate being movable forwardly through the bucket by the link according to positive interaction between the ejector lever and tilt linkage lever after initial forward tilting of the bucket by the tilt linkage.

2. The combination of claim 1 wherein said ejector lever is pivotally joined to said ejector link, said actuating levers having contacting surfaces radially extending from their common pivotal connection, said contacting lever surfaces coming into positive contact with each other to subsequently pivot the ejector plate forwardly according to forward tilting of the bucket only after initial forward tilting of the bucket is effected.

3. The combination of claim 2 wherein one of said levers is a tilt linkage lever which is also pivotally connected to a midportion of the lift arm and a member of the tilt linkage extends from a pivotal connection with the bucket to a pivotal connection with said tilt linkage lever, said pivotal connection of said member with the tilt linkage lever being interposed on the tilt linkage lever between its respective pivotal connections with the lift arm and said ejector link.

4. The combination of claim 3 wherein said ejector link is connected to the ejector at a suitable point for achieving a desirable mechanical advantage in the pivoting of the ejector plate by the tilt linkage.

5. The combination of claim 3 wherein a first mechanical stop is operatively disposed with relation to the ejector plate to limit its forward pivotal motion.

6. The tractor loader of claim 3 wherein the geometry of the lift arms, tilt linkage and said actuating levers are selected to insure that, when the bucket is positioned by the lift arms at preferred dumping height, said tilt linkage lever acts against said other ejector lever to position the sweeping edge of the ejector plate at the forward edge of the bucket floor when the bucket is in a tilted position to have its floor substantially level.

7. The tractor loader of claim 6 wherein the geometry of the lift arms, tilt linkage and said actuating levers are selected to insure that, when the bucket is positioned by the lift arms approximately at ground level and the bucket is forwardly tilted by the tilt linkage to have its forward cutting edge suitably disposed with relation to the ground for bulldozing, said ejector link positions an edge of the ejector plate upon the cutting edge of the bucket to provide a bulldozing surface above the cutting edge of the bucket.

8. A bucket loader disposed on a tractor and having:

a bucket with a floor having a substantially straight outside surface and an arcuate inside surface, an ejector plate forming the rear wall of the bucket and being pivotally connected to the bucket to permit forward and rearward pivoting of the ejector pate such that an edge of the plate sweeps along the arcuate surface of the bucket floor;

a pair of lift arms pivotally connected to the bucket and extending rearwardly to the tractor, said lift arms operable by hydraulic jacks for raising and lowering the bucket;

tilt linkage operable by a pair of hydraulic jacks for forwardly and rearwardly tilting said bucket about its pivot connections with the lift arms, said tilt linkage having a first pair of members, each operably connected to one of the pair of jacks, each of said first members pivotally connected to a lever which is also pivotally connected to one of said lift arms and a second pair of members each pivotally connected between one of said tilt linkage levers and said bucket, each of said levers having an ejector lever pivot connection remotely disposed from its pivot connection with one of said lift arms and an upper contacting edge radially projecting generally rearwardly from said ejector lever pivot connection; and

pair of ejector levers, each pivotally connected between one of the ejector lever pivot connections of said tilt linkage levers and said ejector plate, each of said ejector levers having a rearward contacting 3,349,934 10/ 19 67 Moyer et a1. 214767 surface radially projecting from its pivot connection with one of said tilt linkage levers, said ejector lever contacting surfaces being contacted by said contacting surfaces of said tilt linkage levers after initial forward tilting of said bucket to result in subsequent forward pivoting of said ejector plate according to forward tilting operation of said pair of tilt linkage jacks, said ejector levers comprising stops for limiting pivotal separation of each adjacent pair of said contacting surfaces on one of said ejector levers and one of said tilt linkage levers.

References Cited UNITED STATES PATENTS 2/1964 Campbell et a1 214-146 HUGO O. SCiI-IULZ, Primary Examiner.

US. Cl. X.R. 

